(1st small section from Maddie's Mystery)
‘Mummy what is it?’ I asked. ‘It’s a mystery’ mummy whispered. A mystery? What’s a Mystery? I wondered. Is it a pet? Is it a toy? Ooh I hoped it was both. It was a mystery, it was mine and I named it Maddie’s mystery. I was going to find out what it was. I decided to inspect the box. It was wider than I could stretch my arms apart. Very wide. It was taller than my daddy, and was shaped like square block. This is exciting.
(2nd small section from Maddie's Mystery)
‘Shall I give you some clues, to help you discover what the mystery is?’ mummy asked. ‘Ooh yes please mummy’ I beamed. So, I followed her into the living room skipping as I went. The excitement was bubbling inside me. I stood next to the box, patiently waiting for the first clue. ‘It is big, it is red and it is fun’ mummy declared. Ooh ooh, I know I know. ‘Is it a ball mummy?’ I asked. Mummy started chuckling, ‘Must be a very big ball’ she said.
I was thinking bicycle... but "taller than my daddy"! Unless her daddy is a midget...
Some people are worried about posting a longer piece here, in case others steal it. But remember that once it's visible, it's copyright. Lorraine is right: we need to see more in order to give more useful advice.
Unlike Q&As and replies, shared works can be edited after posting, so that you don't need to post an extended version as a separate work.
What's in that box?
These are very short excerpts, Rebekah, so not much to go on!
Are you looking back as an older person at the events shown, and so describing the child's reaction from a distance in time, or are you telling the story as it happens? It makes a difference. We don't know the age of the child from these pieces.
There are a few things you could do to tidy up a little (other than punctuation):
Everything is past tense in the first section except the last line, which has slipped into present; you should change this, or make it part of the child's speech or thought (see below).
Shaped like square block, or like a square block?
When Mummy is used as a name, it has a capital: 'Mummy whispered'. If it was 'my mummy whispered' it wouldn't.
I'd capitalise Maddie's Mystery too, as she says she's using it as a title, and it makes it more important.
'Ooh I hoped' in the first part; 'Ooh ooh, I know I know.' in the second. You need to be consistent, and make these either both past or both present; or, if they are the child's thoughts, you could put them in present and in italics.
I want to know what's in the box!
Hope this helps.
Lorraine